#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
class Solution {
public:
    int percentageLetter(string s, char letter) {
        int cnt = 0;
        for (auto c : s) {
            if (c == letter) cnt++;
        }
        return 100* cnt / s.size();
    }
};
int main(){
    cout << Solution().percentageLetter("foobar",'o') << endl;
	return 0;
}